Protein kinases (PKs) represent a large family of proteins, which play an important role in the regulation of a wide variety of cellular processes and maintaining control over cellular functions. There are two classes of protein kinases (PKs): the protein tyrosine kinases (PTKs) and the serine-threonine kinases (STKs). The protein tyrosine kinase is an enzyme that catalytically transfers the phosphate group from ATP to the tyrosine residue located at the protein substrate, and has a play in the normal cell growth. Many growth factor receptor proteins operate via the tyrosine kinase, and influence the conduction of signal passage and further regulate the cell growth by this process. However, in some circumstances, these receptors become abnormal due to either mutation or overexpression, which cause the uncontrolled cell multiplication, cause the tumor growth, and finally initiate the well-known disease, i.e., cancer. The growth factor receptor protein tyrosine kinase inhibitor, via the inhibition of the above phosphorylation process, may treat cancers and other diseases characterized by the uncontrolled or abnormal cell growth.
Epidermal growth factor receptor (EGFR), a kind of receptor tyrosine kinases, is a multifunction glycoprotein that is widely distributed on the cell membranes of the tissues of the human body, and is an oncogene analog of avian erythroblastic leukemia viral (v-erb-b). Human EGFR/HER1/ErbB-1 and HER2 (human epidermal growth factor receptor-2)/ErbB-2/Teu/p185, HER3/ErbB-3, HER4/ErbB-4 and the like are grouped into the HER/ErbB family, and belong to protein tyrosine kinases (PTKs). They are single polypeptide chains, and each is encoded respectively by genes located on different chromosomes. EGFR and the like are expressed in the epithelia-derived tumors such as squamous cell carcinoma of head and neck, mammary cancer, rectal cancer, ovarian cancer, prostate carcinoma, non-small cell lung cancer, and the like, which are associated with cell proliferation, metastasis, and the like. Pan-HER tyrosine kinase inhibitor, via the competitive binding to the kinase catalytic sites in the intracellular region against ATP, blocks the autophosphorylation of intramolecular tyrosine, blocks the tyrosine kinase activation, inhibits HER-2 family activation, and therefore inhibits cell cycle progression, accelerates cell apoptosis, and exerts the therapeutic action.
EGFR, after binding to the ligand, forms a dimer with a subgroup of HER family, and then combines with ATP to activate the tyrosine kinase activity of the EGFR itself. Therefore, the autophosphorylation occurs in several tyrosine sites of the intracellular kinase region. Pan-HER tyrosine kinase inhibitor, via simultaneity acting on EGFR and HER2/4, inhibits the activation of HER family, and plays a good role in the tumor growth inhibition.
It is indicated in the study that Pan-HER tyrosine kinase irreversible inhibitor has an inhibition effect on HER2/4, besides it effectively inhibits EGFR. The pharmaceutical drugs of this kind, having an irreversible inhibition to both of HER/ErbB families, not only increase the drug activity, but also reduce the drug resistance, and have a substantial inhibition effect on H1975 cell lines which are resistant to erlotinib.
The pharmaceutical drugs that are now commercially available include selective EGFR tyrosine kinase inhibitor gefitinb (IRESSA®, ZD1839), erlotinib (TARCEVA®, OSI-774), double EGFR/HER2 inhibitor Lapatinib (TYKERB®, GW572016), and the like. These three drugs are all reversible EGF receptor tyrosine phosphorylation kinase inhibitor. It has been found in the study that they have good therapeutic response to some tumors initially. However, several months after the treatment, the disease progression appears again and therefore a natural or secondary drug resistance forms. For example, about half of the patients administered with gefitinib or erlotinib develop resistance to gefitinib or erlotinib, which can not lead to the desired therapeutic effect. And it has been indicated by study that the development of drug resistance to selective EGFR tyrosine kinase inhibitor relates to mutations in EGFR.
The mutations of EGFR gene mostly located in the tyrosing kinase coding domain (TK, exons 18-21) are mainly deletion mutation in exon 19 and point mutation in exon 21, both of which are drug-sensitive, and few are point mutation in exon 18 and insertion mutation in exon 20. T790M mutation recognized as one of the mechanism of drug resistance is a point mutation in exon 20 of EGFR. The presence of a second-site EGFR mutation leads to the substitution of methionine for threonine at position 790 (T790M) and changes in the structure of EGFR, which hinder the binding of EGFR inhibitors to EGFR or greatly increase the affinity between EGFR and ATP, so that ATP affinity back to the level of wild-type EGFR, thus resulting in drug resistance. Further studies shows that the pre-treatment tumor samples with mutations of EGFR contain T790M mutation, which indicates that T790M mutation is not just associated with drug resistance and it may have the carcinogenic potential itself.
Irreversible inhibitor can bind to EGFR tyrosine kinase by covalent bond. Thus, the drugs can act on the entire link of epidermal growth factor signal transduction pathway, and improve efficiency of drug blocking. Many clinical studies show that some irreversible inhibitors in current development can against T790M mutation, and overcome the drug resistance caused by T790M. Meanwhile, listed drug Afatinib (BIBW 2992) and some irreversible inhibitors in clinical development (e.g., Dacomitinib, PF00299804, etc.), can inhibit multiple members of EGFR receptor family, especially to the role of EGFR and HER-2, possibly by blocking collaborative signal pathway activated by homodimer and heterodimer to enhance inhibitory effect (Oncologist, 2009, 14 (11): 1116-1130).
Upon developing the drug having an excellent antineoplastic effect, being able to reduce the drug resistance and having a good tolerance, the present inventors discover a quinazoline derivatives as tyrosine kinase inhibitors having a Pan-HER irreversible inhibition function.